Method for producing light reflective film, and light reflective film

ABSTRACT

A light reflective film is produced by (a) forming an antistatic layer having a surface energy of at least 30 mN/m on a resin film, (b) applying a curable liquid crystal composition onto the surface of the opposite side, (c) drying the applied curable liquid crystal composition to be in a state of a cholesteric liquid crystal phase, (d) promoting the curing reaction to form a light reflective layer, and (e) repeating at least once the process of from (b) to (d).

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority from JapanesePatent Application No. 2010-164985, filed on Jul. 22, 2010, the contentsof which are herein incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for producing a lightreflective film having a light reflective laminate film that includesplural layers each having a cholesteric liquid crystal phase fixedtherein, especially to a method for producing such a light reflectivefilm to be stuck to windows of buildings, car windows, etc. Theinvention also relates to the light reflective film produced accordingto the production method of the invention.

2. Description of the Related Art

Recently, with the increase in the interest in environment and energy,the needs for energy-saving industrial products are high, and as one ofthem, glass and films are desired that are effective for heat shieldsfor windowpanes in houses, cars and the like, or that is, for reducingthermal load from sunlight through windowpanes. For reducing the thermalload from sunlight, it is necessary to prevent transmission of the sun'srays in any of the visible range or IR range of the sunlight spectrum.In particular, for car windows, high transmittance in the visible lightrange is desired from the viewpoint of safety, and the need for heatshielding is also high, and in some countries, there is a tendency toregulate solar reflectance.

Double glass coated with a particular metal film capable of shieldingagainst thermal radiation, which is called low-E pair glass, is wellused as eco-glass having high heat insulating/shielding capability. Theparticular metal film may be formed, for example, by laminating plurallayers according to a vacuum film formation method. The particular metalfilm coating to be formed through vacuum film formation is extremelyexcellent in reflectivity, but the vacuum process is nonproductive andthe production cost thereof is high. In addition, the metal film, whenused, concurrently shields against electromagnetic waves, and istherefore problematic in that, when used in mobile phones and the like,it causes radio disturbance, and when used for automobiles, ETC couldnot be used therein. Not only solving the problem of radio disturbancebut also high transmittance of visible light is desired for car windowsfrom the viewpoint of safety.

A method of using a cholesteric liquid crystal phase in a lightreflective film has been proposed. For example, as disclosed in JapanesePatent 4109914, by forming one cholesteric liquid crystal layer on bothsides of a λ/2 plate, a light circularly-polarized in one direction canbe selectively and efficiently reflected within a range of from 700 to1200 nm.

JP-T 2009-514022 discloses an IR-reflective article having a cholestericliquid crystal layer. Regarding lamination of plural cholesteric liquidcrystal layers, there have been made various attempts to use thelaminate in liquid crystal display devices, and concretely, there areknown various approaches to a technique of efficiently reflecting lightin a visible light region; and for example, Japanese Patent 3500127discloses a case of lamination of multiple cholesteric layers. InExamples in Japanese Patent 3500127, a step of applying a cholestericliquid crystal material to an alignment film-coated glass substratefollowed by curing it thereon is repeated to produce the intendedlaminate.

Japanese Patent 4008358 discloses a method for producing a broadbandcholesteric liquid crystal film through UV-polymerization of apredetermined liquid crystal mixture between two substrates. However,there is given no concrete description relating to a method forproducing a laminate film including plural layers. Japanese Patent3745221 discloses a circularly-polarized light extracting optical devicein which plural liquid crystal layers each formed of three-dimensionallycrosslinked liquid crystal molecules having cholesteric regularity arelaminated under a predetermined condition. In Examples in JapanesePatent 3745221, a coating liquid of a liquid crystal material is appliedonto a glass substrate in a mode of spin coating and thereafter theliquid crystal molecules are three-dimensionally crosslinked throughirradiation with light to form the constitutive layers, therebyproducing a laminate-structured device.

JP-A 2002-22960 discloses a case of configuration having an antistaticlight-diffusive layer formed on one side or both sides of a cholestericlayer. JP-A2004-252257 discloses a case of configuration having anantistatic layer formed by applying an antistatic agent to the surfaceand/or the back of a light-diffusive sheet.

SUMMARY OF THE INVENTION

For producing a reflective film of high heat shieldability, thereflection wavelength band must be broadened, and in general, for widerbandwidth, a laminate structure composed of multiple light reflectivelayers each having a different selective reflection wavelength isgenerally employed. The light reflective film having a laminatestructure may be produced, for example, in a mode of successive coatingwith constitutive layers to be laminated or in a mode of laminatingplural layers by sticking. In the former method, in general, a coatingstep, a drying step, an alignment step and a curing step are repeated,in which for curing, for example, photocuring through UV irradiation isemployed. In an ordinary coating apparatus, there are provided from 1 to3 coating steps, and for forming plural layers in the apparatus, thefilm being produced must be once wound up as a roll, then unrolled, andrepeatedly processed in a process of coating, drying, alignment andcuring steps. The present inventors actually investigated the process ofthese steps and have known that, in case where the laminate film is oncewound up, the coating film and the substrate film are kept in strongcontact with each other under tension given thereto, and therefore thereis a problem in that, when the coating film is formed on the unrolledlaminate film, then the light reflectance thereof lowers. On the otherhand, there is known a problem of stickiness such as blocking or thelike regarding the influence of the contact between a coating film andthe back surface of a resin film, and there is known a countermeasurethereagainst of lowering the surface energy on the back of the film.However, in this case, there occurs a problem in that, when a hard coatlayer is formed on the back of the film, the coating film is repelledand a flat and smooth film could not be formed. Such a hard coat layermay be an indispensable component in some applications and useembodiments of light reflective films, and accordingly, it is desired tosatisfy both the requirement of preventing the light reflective filmperformance from being worsened owing to the operation of winding upinto a roll and unrolling the rolled film in forming plural layers eachhaving a cholesteric liquid crystal phase fixed therein, and therequirement of forming a hard coat layer of good quality on the back ofthe film.

However, nothing is referred to in any reference, relating to thedeterioration of the performance of the light reflective film to becaused by the operation of winding up into a roll and unrolling therolled film in forming a plurality of layers each having a cholestericliquid crystal phase fixed therein. On the other hand, Patent Reference2 says that a metal layer may be provided adjacent to a cholestericliquid crystal layer or a hard coat layer may be provided, in which,however, nothing is investigated relating to the surface energy of thefilm surface on the side not laminated with the cholesteric liquidcrystal layer and relating to the formation aptitude of the hard coatlayer. JP-A 2002-22960 and JP-A 2004-252257 describe addition ofelectroconductive inorganic fine particles or light-diffusive silica toan antistatic light-diffusive layer, in which, however, nothing isinvestigated relating to the surface energy of the surface of theantistatic light-diffusive layer but the surface of the layer is ratherroughened to have irregularities, and nothing is also investigatedrelating to the coatability of the surface with any additionalfunctional layer.

The present invention has been made in consideration of theabove-mentioned problems. Specifically, an object of the invention forsolving the problems is to provide a light reflective film whichcontains a plurality of layers each having a cholesteric liquid crystalphase fixed therein, which can still maintain good IR reflectivity in abroadband range even after repeated operation of winding up into a rolland unrolling the roll, which has a small haze and of which thecoatability with a hard coat layer is good.

The present inventors have assiduously studied for the purpose ofsolving the above-mentioned problems. As a result, the inventors havefound that, in general, when the surface energy of a substrate film isincreased, then the coatability thereof with a hard coat layer may bebettered, but on the contrary, the haze of the film increases and thelight reflectance thereof lowers, or that is, the two are in a tradeoffrelation. Regarding this, the inventors have promoted further studies.Concretely, the inventors have laminated an antistatic layer on thesurface of the resin film on the side thereof not laminated with acholesteric liquid crystal layer, and have found surprisingly that evenwhen the surface energy of the film is increased, the haze of the filmdoes not increase and the light reflectance thereof does not lower.Specifically, the present inventors have found that the above-mentionedproblems can be solved by the following constitution, and have completedthe present invention. The invention comprises the followingconstitution.

[1] A method for producing a light reflective film, comprising (a)forming an antistatic layer having a surface energy of at least 30 mN/mon one surface of a resin film to produce a laminate, (b) applying acurable liquid crystal composition onto the surface of the laminateopposite to the side thereof given the antistatic layer, (c) drying theapplied curable liquid crystal composition to be in a state of acholesteric liquid crystal phase, (d) promoting the curing reaction ofthe curable liquid crystal composition to fix the cholesteric liquidcrystal phase thereby forming a light reflective layer, and (e)repeating at least once the process of from (b) to (d) on the laminatehaving the light reflective layer formed thereon.

[2] The method for producing a light reflective film of [1], wherein thecurable liquid crystal composition contains at least a polymerizablerod-shaped liquid crystal compound, an alignment controlling agentcapable of controlling the alignment of the polymerizable rod-shapedliquid crystal compound, and a solvent.

[3] The method for producing a light reflective film of [1] or [2],wherein in the process of the step (b) to the step (e), at least onelayer of reflecting a right circularly-polarized light and at least onelayer of reflecting a left circularly-polarized light are formed.

[4] The method for producing a light reflective film of any one of [1]to [3], which comprises aligning the surface of the laminate on the sideopposite to the side thereof having the antistatic layer formed thereon,between the step (a) and the step (b).

[5] The method for producing a light reflective film of anyone of [1] to[4], which comprises forming an alignment film on the laminate on theside opposite to the side thereof having the antistatic layer formedthereon, and aligning the surface of the alignment film, between thestep (a) and the step (b).

[6] The method for producing a light reflective film of [4] or [5],which comprises aligning the surface of the laminate by rubbingtreatment.

[7] The method for producing a light reflective film of any one of [1]to [6], which comprises forming the antistatic layer by using anantistatic layer composition containing electroconductive fineparticles.

[8] The method for producing a light reflective film of [7], wherein theantistatic layer composition contains an electroconductive polymer.

[9] The method for producing a light reflective film of any one of [1]to [8], wherein the resin film is a polyethylene terephthalate film.

[10] The method for producing a light reflective film of any one of [1]to [9], which comprises forming a hard coat layer on the surface of theresin film opposite to the side of the antistatic layer thereof.

[11] The method for producing a light reflective film of anyone of [1]to [10], which is for producing a light reflective film to be stuck towindowpanes.

[12] The method for producing a light reflective film of any one of [1]to [11], which comprises winding up the film into a roll.

[13] A light reflective film produced according to the method forproducing a light reflective film of any one of [1] to [12].

[14] The light reflective film of [13] wound up into a roll.

According to the invention, there is provided a method for producing alight reflective film which contains a plurality of layers each having acholesteric liquid crystal phase fixed therein, which can still maintaingood IR reflectivity in a broadband range even after repeated operationof winding up into a roll and unrolling the roll, which has a small hazeand of which the coatability with a hard coat layer is good.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of one example of the light reflectivefilm produced according to the production method of the invention.

FIG. 2 is a cross-sectional view of other example of the lightreflective film produced according to the production method of theinvention.

FIG. 3 is a cross-sectional view of still other example of the lightreflective film produced according to the production method of theinvention.

In the drawings, 1 denotes light reflective film, 10 denotes hard coatlayer, 11 denotes antistatic layer, 12 denotes resin film, and 14 a, 14b, 16 a and 16 b denote light reflective layers.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, the contents of the invention are described in detail.In this description, the numerical range expressed by the wording “anumber to another number” means the range that falls between the formernumber indicating the lowermost limit of the range and the latter numberindicating the uppermost limit thereof. In this description, “lighttransmittance” is meant to indicate that the film is transmissive tovisible light.

[Method for Producing Light Reflective Film]

The method for producing a light reflective film of the invention(hereinafter this may be referred to as the production method of theinvention) includes (a) forming an antistatic layer having a surfaceenergy of at least 30 mN/m on one surface of a resin film to produce alaminate, (b) applying a curable liquid crystal composition onto thesurface of the laminate opposite to the side thereof given theantistatic layer, (c) drying the applied curable liquid crystalcomposition to be in a state of a cholesteric liquid crystal phase, (d)promoting the curing reaction of the curable liquid crystal compositionto fix the cholesteric liquid crystal phase thereby forming a lightreflective layer, and (e) repeating at least once the process of thestep (b) to the step (d) on the laminate having the light reflectivelayer formed thereon.

The production method of the invention includes the above-mentionedconstitution, therefore producing a light reflective film which canstill maintain good IR reflectivity in a broadband range even afterrepeated operation of winding up into a roll and unrolling the roll andwhich has a small haze. The light reflective layer with a cholestericliquid crystal phase fixed therein exhibits light-selective reflectingcharacteristics of reflecting a light falling within a specificwavelength range based on the helical pitch of the cholesteric liquidcrystal phase. Accordingly, by controlling the helical pitch of thecholesteric liquid crystal phase to thereby cut off only the lightfalling within a wavelength range of 700 nm or more, a high-levelheat-shielding effect can be obtained.

The production method of the invention is described below in point ofthe materials preferred therein and the steps constituting the method.

<Step (a)>

The production method of the invention includes (a) a step of forming anantistatic layer having a surface energy of at least 30 mN/m, on onesurface of a resin film to give a laminate.

(Resin Film)

In the production method of the invention, the resin film is notspecifically defined. Depending on the intended purpose thereof, thefilm may be required to have high transparency to UV ray. The film maybe a particular retardation plate such as λ/2 plate or the like that isproduced in a controlled production process, or may also be a polymerfilm or the like that would be unusable as prescribed retardation platessince the fluctuation of the in-plane retardation thereof is too great,concretely, when it is expressed as the fluctuation of the in-planeretardation at a wavelength of 1000 nm, Re (1000), the Re (1000)fluctuation of the film is at least 20 nm, or at least 100 nm.

The in-plane retardation of the resin film is not also specificallydefined. For example, a retardation plate or the like having an in-planeretardation at a wavelength of 1000 nm, Re (1000) of from 800 to 13000nm may be usable.

Depending on the intended purpose thereof, a polymer film having a hightransmittance to visible light is preferably used here as the resinfilm. As the polymer film having a high transmittance to visible light,there may be mentioned various types of polymer films for optical filmsthat are used as parts of display devices such as liquid crystal displaydevices, etc. More concretely, there may be mentioned polyester filmssuch as polyethylene terephthalate (PET), polybutylene terephthalate,polyethylene naphthalate (PEN), etc.; polycarbonate (PC) films,polymethyl methacrylate films; polyolefin films such as polyethylene,polypropylene, etc.; polyimide films, triacetyl cellulose (TAC) films,etc.

In the production method of the invention, the resin film is preferablya polyethylene terephthalate film from the viewpoint of the transparencythereof.

Preferably, the resin film is processed for surface treatment. Themethod of surface treatment is not specifically defined, and any knownmethod is employable. For example, there may be mentioned glow dischargetreatment, plasma discharge treatment, ozone treatment, etc. In theproduction method of the invention, preferably, the antistatic layer islaminated on the surface processed for glow discharge treatment.

(Lamination of Antistatic Layer)

The method for forming an antistatic layer on one surface of the resinfilm to produce a laminate is not specifically defined, for which anyknown method is employable.

As the method of forming the antistatic layer, there may be mentionedcoating and vapor-phase film formation such as sputtering, etc. Aboveall, coating is preferred, and more preferred is one formed by coatingwith a coating liquid that contains a polyfunctional monomer or oligomerfollowed by drying and curing it for obtaining a predetermined hardness.

For the coating method, preferably, the coating liquid is prepared bydissolving and/or dispersing the material in a solvent. Coating with thecoating liquid may be attained in various methods of a wire bar coatingmethod, an extrusion coating method, a direct gravure coating method, areverse gravure coating method, a die coating method, etc. As the casemay be, an inkjet apparatus may be used, in which a liquid crystalcomposition may be jetted out through the nozzle to form a coating film.

(Resin to be Contained in Composition for Antistatic Layer)

The material to be used in forming the antistatic layer is notspecifically defined. Various materials heretofore used as those forantistatic layer formation on a polymer film (for example, PET film) maybe used here.

On the other hand, the antistatic layer composition preferably contains,as the main ingredient thereof, at least one difunctional or morepolyfunctional polymerizing monomer. The difunctional or morepolyfunctional polymerizing monomer is preferably a difunctional or morepolyfunctional (meth)acrylate. In this description, “(meth)acrylate”means a generic term of methacrylate and acrylate; and the difunctionalor more polyfunctional monomer means a monomer that contains at leasttwo polymerizing groups in one molecule.

Preferably, the difunctional or more polyfunctional (meth)acrylate isphotopolymerizable. Depending on the desired pencil hardness, one aloneor two or more different types of difunctional or more polyfunctional(meth)acrylates may be used here either singly or as combined. As thedifunctional or more polyfunctional (meth)acrylate, herein usable areany known ones; and above all, preferred is use of 1,9-nonanediolacrylate, dipentaerythritol hexaacrylate (DPHA) or pentaerythritoltetraacrylate (PETA) from the viewpoint of securing the hardness.

The method of controlling the surface energy of the antistatic layer tobe at least 30 mN/m is not specifically defined, for which any knownmethod is employable.

Preferably, the production method of the invention includes the step offorming the antistatic layer by using an antistatic layer compositioncontaining a fluorine compound.

Preferably, the fluorine compound is a (meth)acrylate having aβ-(perfluoroalkyl) group, as capable of giving high water repellency.

The fluorine compound may be commercially available, for which, forexample, preferably used are Light Acrylate FA-108, trade name byKyoeisha Chemical Industry, etc.

The amount of the fluorine compound to be added is preferably from 0.05to 80% by mass relative to the mass of the entire antistatic layer, morepreferably from 0.1 to 60% by mass, even more preferably from 0.2 to 50%by mass.

The antistatic layer is described. In the method of givingelectroconductivity to the layer, there may be used moisture-absorbingsubstances, water-soluble inorganic salts, some types of surfactants,cationic polymers, anionic polymers, colloidal silica, metal particles,etc. For completely preventing dust adhesion, preferably,electroconductivity on a level of volume resistivity of at most 10⁻⁸(Ωcm⁻³) is given to the layer. Use of moisture-absorbing substances,water-soluble inorganic salts, some types of surfactants, cationicpolymers, anionic polymers, colloidal silica and the like may make itpossible to give a volume resistivity of at most 10⁻⁸ (Ωcm⁻³) to thelayer, which, however, is problematic in that the temperature-humiditydependence is great and therefore a high humidity in some degree isneeded for securing sufficient electroconductivity. Accordingly, theproduction method of the invention preferably includes the step offorming the antistatic layer by using an antistatic layer compositioncontaining electroconductive fine particles. Therefore, as the materialsto be used in the electroconductive layer, preferred are metal oxidescomprising, as the main ingredient thereof, any of Zn, Ti, Al, In, Si,Mg, Ba, Mo, W, V and Sn. As concrete examples, preferred are ZnO, TiO₂,SnO₂, Al₂O₃, In₂O₃, SiO₂, MgO, BaO, MoO₃, V₂O₅ and the like, and theircomposite oxides, and more preferred are ZnO, TiO₂, SnO₂. Regardingexamples containing a hetero atom, for example, Al, In or the like iseffectively added to ZnO; Sb (for example, Sb₂O₅), Nb, halogen elementor the like is to SnO₂; and Nb, TA or the like is to TiO₂. In addition,materials prepared by attaching the above-mentioned metal oxide to anyother crystalline metal particles or fibrous materials (for example,titanium oxide) may also be used, as described in JP-B 59-6235.

Preferred embodiments of the above-mentioned electroconductive fineparticles are described in JP-A 62-270335, and these are favorablyemployed here.

Preferably, the surface energy of the antistatic layer is at least 30mN/m, and the surface energy of the layer is preferably higher from theviewpoint of the coatability of the antistatic layer with a hard coatlayer or the like to be formed thereon.

(Characteristics of Antistatic Layer Composition)

Preferably, the antistatic layer composition has a viscosity of from 1to 100 mPa·s, more preferably from 1 to 30 mPa·s from the viewpoint ofthe coatability thereof.

The coating thickness of the antistatic layer composition is notspecifically defined. After cured, the thickness is preferably from 0.05to 10 μm or so, more preferably from 0.1 to 5 μm, even more preferablyfrom 0.1 to 1 μm.

As shown in Examples to be given hereinunder, the antistatic layer maycontain metal fine particles or may contain an electroconductive polymercapable of providing an antistatic function.

(Coatability of Hard Coat Layer)

In the film of the invention, the coatability of the antistatic layerwith a hard coat layer is good. Concretely, in the film of theinvention, a hard coat layer having high smoothness can be formed withno cissing on the antistatic layer. The hard coat layer and a method forforming it that are preferably employed in the invention are describedbelow.

Regarding the coating method, preferably, the material is dissolvedand/or dispersed in a solvent to prepare a coating liquid, and thecoating liquid is used in the method. For coating with the coatingmethod, employable are various methods of a wire bar coating method, anextrusion coating method, a direct gravure coating method, a reversegravure coating method, a die coating method, etc. As the case may be,an inkjet apparatus may be used, in which the liquid crystal compositionmay be jetted out through the nozzle to form a coating film. (Resin tobe Contained in Composition for Hard Coat Layer)

The material to be used in forming the hard coat layer is notspecifically defined. Various materials heretofore used as those forhard coat layer formation on a polymer film (for example, PET film) maybe used here.

The hard coat layer preferably has a pencil hardness of at least 2H. Themethod of controlling the pencil hardness of the hard coat layer to beat least 2H is not specifically defined, for which any known method isemployable. In this, for example, the hard coat layer compositionpreferably contains, as the main ingredient thereof, at least onedifunctional or more polyfunctional polymerizable monomer, from theviewpoint that the hard coat layer formed after light irradiation orthermal polymerization could be readily controlled to have a pencilhardness of at least 2H. The difunctional or more polyfunctionalpolymerizable monomer is preferably a difunctional or morepolyfunctional (meth)acrylate. In this description, “(meth)acrylate”means a generic term of methacrylate and acrylate; and the difunctionalor more polyfunctional monomer means a monomer that contains at leasttwo polymerizable groups in one molecule.

Preferably, the difunctional or more polyfunctional (meth)acrylate isphotopolymerizable. Depending on the desired pencil hardness, one aloneor two or more different types of difunctional or more polyfunctional(meth)acrylates may be used here either singly or as combined. As thedifunctional or more polyfunctional (meth)acrylate, herein usable areany known ones; and above all, preferred is use of dipentaerythritolhexaacrylate (DPHA) or pentaerythritol tetraacrylate (PETA) from theviewpoint of securing the hardness.

The hard coat layer composition may further contain, in addition to thedifunctional or more polyfunctional (meth)acrylate, a monofunctional(meth)acrylate for the purpose of controlling the viscosity in coatingor the pencil hardness after film formation.

The hard coat layer preferably has a surface energy of less than 30 mN/mon the surface of the side opposite to the side having the antistaticlayer. The method for controlling the surface energy of the hard coatlayer to be less than 30 mN/m is not specifically defined, for which anyknown method is employable.

Preferably, the production method of the invention includes a step offorming the hard coat layer by using a hard coat layer compositioncontaining a fluorine compound.

Preferably, the fluorine compound is a (meth)acrylate having aperfluoroalkyl group, as capable of giving high water repellency.

The fluorine compound may be commercially available, for which, forexample, preferably used are Light Acrylate FA-108, trade name byKyoeisha Chemical Industry, etc.

The amount of the fluorine compound to be added is preferably from 0.05to 80% by mass relative to the mass of the entire hard coat layer, morepreferably from 0.1 to 60% by mass, even more preferably from 0.2 to 50%by mass.

Preferably, the surface energy of the hard coat layer is from 5 to 29mN/m, even more preferably from 5 to 20 mN/m. When the surface energy ofthe hard coat layer is less than 30 mN/m and when the hard coat layer ofthe type is laminated on the antistatic layer of the film of theinvention, the invention can provide a light reflective film which canstill maintain good IR reflectivity in a broadband range even afterrepeated operation of winding up into a roll and unrolling the roll andwhich has a small haze.

Also preferably, the production method of the invention includes a stepof forming the hard coat layer by using a hard coat layer compositioncontaining a silicon compound from the viewpoint of the soil resistanceof the layer of facilitating easy removal of the fingerprints and soilhaving adhered thereto. As the silicon compound, there may be mentionedsilicon rubber and silicon acrylic monomer; and preferably, the layercontains silica particles from the viewpoint of increasing the surfaceharness thereof. (Characteristics of Hard Coat Layer Composition)

Preferably, the viscosity of the hard coat layer composition is from 1to 100 Pa·s from the viewpoint of the coatability thereof, morepreferably from 1 to 30 Pa·s.

The coating thickness of the hard coat layer composition is notspecifically defined. After cured, the thickness is preferably from 0.1to 15 μm or so, more preferably from 1 to 10 μm, even more preferablyfrom 3 to 8 μm.

(Alignment Treatment of Surface of Laminate)

Preferably, the production method of the invention includes a step ofaligning the surface of the laminate on the side opposite to the sidethereof having the antistatic layer formed thereon, between the step (a)and the step (b). The alignment treatment method is not specificallydefined, for which employable is a method of using an alignment film.

Preferably, the production method of the invention includes a step offorming an alignment film on the laminate on the side opposite to theside thereof having the antistatic layer formed thereon, and a step ofaligning the surface of the alignment film, between the step (a) and thestep (b). The alignment film is not specifically defined, for which anyknown alignment film is usable. The film may be a rubbing alignment filmor any other optical alignment film. Above all, preferred is use of arubbing alignment film, or that is, the production method of theinvention preferably includes a step of aligning the surface of thelaminate by rubbing treatment.

<Step (b)>

The production method of the invention includes (b) a step of applying acurable liquid crystal composition onto the surface of the laminateopposite to the side thereof given the antistatic layer.

(Coating Method)

In the step (b), the curable liquid crystal composition is applied ontothe surface of the laminate, or that is, onto the surface of resin filmor the underlying light reflective layer. The coating method with thecurable liquid crystal composition is not specifically defined, forwhich any known method is employable. Preferably, the material isdissolved and/or dispersed in a solvent to prepare a coating liquid. Thecoating liquid may be applied according to various methods of a wire barcoating method, an extrusion coating method, a direct gravure coatingmethod, a reverse gravure coating method, a die coating method, etc. Asthe case may be, an inkjet apparatus may be used, in which the liquidcrystal composition may be jetted out through the nozzle to form acoating film.

(Curable Liquid Crystal Composition)

Next described are the materials to be contained in the curable liquidcrystal composition.

Preferably, the curable liquid crystal composition for forming the lightreflective layer contains, for example, at least a rod-shaped liquidcrystal compound, an alignment controlling agent capable of controllingthe alignment of the rod-shaped liquid crystal compound, and a solvent;and more preferably, the rod-shaped liquid crystal compound is apolymerizable rod-shaped liquid crystal compound.

Also preferably, the curable liquid crystal composition contains atleast a rod-shaped liquid crystal compound, an optically-active compound(this may be referred to as a chiral agent), and a polymerizationinitiator.

More preferably, the composition contains a polymerization initiator.The composition may contain two or more different types of therespective ingredients. For example, both a polymerizable liquid crystalcompound and a non-polymerizable liquid crystal compound may be in thecomposition. Both a low-molecular liquid crystal compound and ahigh-molecular liquid crystal compound may also be in the composition.

In addition, for the purpose of enhancing the alignment uniformity andthe coating aptitude and increasing the film strength, the compositionmay contain at least one selected from various additives of a horizontalalignment agent, a unevenness inhibitor, a cissing improver, apolymerizable monomer, etc. If desired, a polymerization inhibitor, anantioxidant, a UV absorbent, alight stabilizer and the like may befurther added to curable liquid crystal composition within a range notdetracting from the optical performance of the film.

The materials preferably contained in the curable liquid crystalcomposition are described below.

(1) Polymerizable Rod-Shaped Liquid Crystal Compound:

One example of the rod-shaped liquid crystal compound usable in theinvention is a rod-shaped nematic liquid crystal compound. Preferredexamples of the rod-shaped nematic liquid crystal compound areazomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters,benzoates, phenyl cyclohexanecarboxylates, cyanophenylcyclohexanes,cyano-substituted phenylpyrimidines, alkoxy-substitutedphenylpyrimidines, phenyldioxanes, tolanes andalkenylcyclohexylbenzonitriles. Not only low-molecular liquid crystalcompounds but also high-molecular liquid crystal compounds are usablehere.

The rod-shaped liquid crystal compound for use in the invention may bepolymerizable or non-polymerizable. Rod-shaped liquid crystal compoundsnot having a polymerizable group are described in various references(for example, Y. Goto, et. al., Mol. Cryst. Liq. Cryst. 1995, Vol. 260,pp. 23-28).

The polymerizable rod-shaped liquid crystal compound may be obtained byintroducing a polymerizable group into a rod-shaped liquid crystalcompound. Examples of the polymerizable group include an unsaturatedpolymerizable group, an epoxy group and an aziridinyl group. Preferredis an unsaturated polymerizable group, and more preferred is anethylenic unsaturated polymerizable group. The polymerizable group maybe introduced into the molecule of a rod-shaped liquid crystal compoundin various methods. The number of the polymerizable groups that thepolymerizable rod-shaped liquid crystal compound has is preferably from1 to 6, more preferably from 1 to 3. Examples of the polymerizablerod-shaped liquid crystal compound includes the compounds described inMakromol. Chem., Vol. 190, p. 2255 (1989); Advanced Materials, Vol. 5,p. 107 (1993); U.S. Pat. Nos. 4,683,327, 5,622,648, 5,770,107;WO95/22586, WO95/24455, WO97/00600, WO98/23580, WO98/52905; JP-A1-272551, 6-16616, 7-110469, 11-80081, 2001-328973, etc. Two or moredifferent types of polymerizable rod-shaped liquid crystal compounds maybe used here as combined. When two or more different types ofpolymerizable rod-shaped liquid crystal compounds are used as combined,the alignment temperature may be lowered.

(2) Alignment Controlling Agent:

An alignment controlling agent that contributes toward stable and rapidformation of the cholesteric liquid crystal phase may be added to thecurable liquid crystal composition. Examples of the alignmentcontrolling agent include compounds of the following general formulae(I) to (IV). Two or more of the compounds may be selected to beincluded. These compounds can reduce the tilt angle of the molecule of aliquid crystal compound or can align the molecule substantiallyhorizontally in the interface of the layer to air. Further, thecompounds of the following formulae (I) to (IV) are all excellent indiffusibility from lower layer to upper layer, and are thereforeespecially useful as the alignment controlling agent in the method ofthe invention.

In this description, “horizontal alignment” means that the long axis ofa liquid crystal molecule is parallel to the film face, but does notrequire strict parallelness; and in this description, “horizontalalignment” means that the tilt angle to the horizontal face is less than20 degrees. In case where a liquid crystal compound aligns horizontallynear the interface to air, there may hardly occur alignment deficiencyand therefore the transparency in the visible light region couldincrease and the reflectance in the IR region could also increase. Onthe other hand, when the molecules of liquid crystal compound align at alarge tilt angle, then the helical axis of the cholesteric liquidcrystal phase may shift from the normal line to the film face and thecase is therefore unfavorable since the reflectance may lower, fingerprint patterns may occur and the haze may increase to exhibitrefraction.

In the above formulae, R's may be the same or different, eachrepresenting an alkoxy group having from 1 to 30 carbon atoms andoptionally substituted with a fluorine atom, preferably an alkoxy grouphaving from 1 to 20 carbon atoms, more preferably an alkoxy group havingfrom 1 to 15 carbon atoms. However, one or more CH₂'s in the alkoxygroup or two or more CH₂'s not adjacent to each other therein may besubstituted with —O—, —S—, —OCO—, —COO—, —NR^(a)—, —NR^(a)CO—,—CONR^(a)—, —NR^(a)SO₂—, or —SO₂NR^(a)—; and R^(a) represents a hydrogenatom or an alkyl group having from 1 to 5 carbon atoms. Preferably, thecompound has at least one fluorine atom, since many molecules of thecompound of the type may be distributed as eccentrically located in theinterface to air and can be readily dissolved and diffused out into theupper layer. Preferably, the terminal carbon atom of the compound issubstituted with a fluorine atom, and also preferably the compound has aperfluoroalkyl group at the terminal thereof.

Preferred examples of R are:

-   —OC_(n)H_(2n+1)-   —(OC₂H₄)_(n1)(CF₂)_(n2)F-   —(OC₃H₆)_(n1)(CF₂)_(n2)F-   —(OC₂H₄)_(n1)NR^(a)SO₂(CF₂)_(n2)F-   —(OC₃H₆)_(n1)NR^(a)SO₂(CF₂)_(n2)F

In the above formulae, n, n1 and n2 each indicate an integer of 1 ormore; n is preferably from 1 to 20, more preferably from 5 to 15; n1 ispreferably from 1 to 10, more preferably from 1 to 5; n2 is preferablyfrom 1 to 10, more preferably from 2 to 10.

In the above formulae, m1, m2 and m3 each indicate an integer of 1 ormore.

Preferably, m1 is 1 or 2, more preferably 2. When m1 is 1, R ispreferably para-positioned, and when 2, R is preferably meta- andpara-positioned.

Preferably, m2 is 1 or 2, more preferably 1. When m2 is 1, R ispreferably para-positioned, and when 2, R is preferably meta- andpara-positioned.

Preferably, m3 is from 1 to 3, and more preferably, R is at two metapositions and at one para-position relative to —COOH.

Examples of the compounds of the above-mentioned formula (I) include thecompounds shown in [0092] and [0093] in JP-A 2005-99248.

Examples of the compounds of the formula (II) include the compoundsshown in [0076] to [0078] and [0082] to [0085] in JP-A 2002-129162.

Examples of the compounds of the formula (III) include the compoundsshown in [0094] and [0095] in JP-A 2005-99248.

Examples of the compounds of the formula (IV) include the compoundsshown in [0096] in JP-A 2005-99248.

The amount of the alignment controlling agent to be in the curableliquid crystal composition is preferably from 0.01 to 10% by mass of themass of the liquid crystal compound therein, more preferably from 0.02to 1% by mass.

(3) Solvent:

The solvent in the curable liquid crystal composition is notspecifically defined, for which any known solvent for liquid crystalcompound is usable. The type of the solvent is not also specificallydefined. For example, as the solvent, there may be mentioned ketones(acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, etc.);ethers (dioxane, tetrahydrofuran, etc.); aliphatic hydrocarbons (hexane,etc.); alicyclic hydrocarbons (cyclohexane, etc.); aromatic hydrocarbons(toluene, xylene, etc.); halogenohydrocarbons (dichloromethane,dichloroethane, etc.); esters (methyl acetate, ethyl acetate, butylacetate, etc.); water; alcohols (ethanol, isopropanol, butanol,cyclohexanol, etc.); cellosolves (methyl cellosolve, ethyl cellosolve,etc.); cellosolve acetates; sulfoxides (dimethyl sulfoxide, etc.);amides (dimethylformamide, dimethylacetamide, etc.); etc. In theproduction method of the invention, use of 2-butanone is more preferredfrom the viewpoint of the solubility of the solid ingredients and thedrying efficiency of the coating film. On the other hand, for easydissolution of the alignment controlling agent therein, a solvent havinga high polarity may also be sued. Concretely, toluene, methyl ethylketone, N-methylpyrrolidone or the like is preferred for the case. Oneor more such solvents may be used here either singly or as combined.

From the viewpoint of the coating film formability and the productionefficiency, the solid concentration in the curable liquid crystalcomposition is preferably from 10 to 50%, more preferably from 15 to40%.

(4) Optically-Active Compound (Chiral Agent):

The curable liquid crystal composition exhibits a cholesteric liquidcrystal phase, for which the composition preferably contains anoptically-active compound. However, in case where the rod-shaped liquidcrystal compound is a molecule having an asymmetric carbon atom, theremay be a case where the composition could stably form a cholestericliquid crystal phase even though an optically-active compound is notadded thereto. The optically-active compound may be selected fromvarious known chiral agents (for example, as described in Liquid crystalDevice Handbook, Chap. 3, Item 4-3, Chiral Agents for TN and STN, p.199, by the 142nd Committee of the Japan Society for the Promotion ofScience, 1989). The optically-active compound generally contains anasymmetric carbon atom; however, an axial asymmetric compound or aplanar asymmetric compound not containing an asymmetric carbon atom mayalso be used here as the chiral agent. Examples of the axial asymmetriccompound or the planar asymmetric compound include binaphthyl, helicene,paracyclophane and their derivatives. The optically-active compound(chiral agent) may have a polymerizable group. In case where theoptically-active compound has a polymerizable group and the rod-shapedliquid crystal compound to be used concurrently also has a polymerizablegroup, a polymer may be formed through polymerization of thepolymerizable optically-active compound and the polymerizable rod-shapedliquid crystal compound, which has a recurring unit derived from therod-shaped liquid crystal compound and a recurring unit derived from theoptically-active compound. In this embodiment, preferably, thepolymerizable group which the polymerizable optically-active compound isa group of the same type as that of the polymerizable group which thepolymerizable rod-shaped liquid crystal compound. Accordingly,preferably, the polymerizable group of the optically-active compound isalso an unsaturated polymerizable group, an epoxy group or an aziridinylgroup, more preferably an unsaturated polymerizable group, even morepreferably an ethylenic unsaturated polymerizable group.

The optically-active compound may be a liquid crystal compound.

The amount of the optically-active compound in the curable liquidcrystal composition is preferably from 1 to 30 mol % of the liquidcrystal compound therein. The amount of the optically-active compound inthe composition is preferably smaller in order that the compound doesnot have any influence on the liquid crystallinity of the composition.Accordingly, the optically-active compound to be used as a chiral agentin the composition is preferably a compound having a strong torsionforce in order that the compound could attain the desired helical pitchtorsion alignment even though its amount used is small. As the chiralagent having such a strong torsion force, for example, there may bementioned the chiral agents described in JP-A 2003-287623, and these arefavorably used also in the invention.

(5) Polymerization Initiator:

The curable liquid crystal composition for forming the light reflectivelayer is preferably a polymerizable liquid crystal composition, forwhich, therefore, the composition preferably contains a polymerizationinitiator. One embodiment of the polymerizable liquid crystalcomposition is a UV-curable liquid crystal composition that contains aphotopolymerization initiator capable of initiating polymerizationthrough irradiation with UV ray. Examples of the photopolymerizationinitiator include α-carbonyl compounds (as described in U.S. Pat. Nos.2,367,661, 2,367,670), acyloin ethers (as described in USP 2448828),α-hydrocarbon-substituted aromatic acyloin compounds (as described U.S.Pat. No. in 2,722,512), polynuclear quinone compounds (as described inU.S. Pat. Nos. 3,046,127, 2,9517,589), combination of triarylimidazoledimer and p-aminophenyl ketone (as described in U.S. Pat. No.3,549,367), acridine and phenazine compounds (as described in JP-A60-105667, U.S. Pat. No. 4,239,850), oxadiazole compounds (as describedin U.S. Pat. No. 4,212,970), etc.

The amount of the photopolymerization initiator to be used is preferablyfrom 0.1 to 20% by mass of the curable liquid crystal composition (orthe solid content of the coating liquid of the composition), morepreferably from 1 to 8% by mass.

(Preparation of Additive)

Preferably, the light reflective film of the invention has a lightreflective layer of such that the peak (maximum level) of the highestwavelength of the light to be reflected by it is at least 700 nm, orthat is, a so-called IR-reflective layer, more preferably, the number ofthe peaks of the wavelength of the light to be reflected by the lightreflective layer is at least one within a range of from 800 to 1300 nm.The selective reflectiveness to light having a wavelength of at least700 nm is attained by the cholesteric liquid crystal phase having ahelical pitch of generally from 500 to 1350 nm or so (preferably from500 to 900 nm or so, more preferably from 550 to 800 nm or so, andhaving a thickness of generally from 1 μm to 8 μm or so (preferably from3 to 8 μm or so).

The selective reflection wavelength of the light reflective layer isdefined by the helical pitch, and the selective wavelength tends toshift toward the lower wavelength side when the incident direction oflight is tilted from the normal line direction relative to the layersurface. Accordingly, for example, the helical pitch is first optimizedrelative to the introduction of light from the normal line direction,then the relationship between the incident angle and the shifting towardthe shorter wavelength side of the selective reflection wavelength isconfirmed through actual measurement, and the helical pitch may becomputed from the measured data. The desired helical pitch to becomputed in that manner can be attained by controlling at least onefactor of the type of the chiral agent, the amount thereof and thepolymerization reactivity.

Specifically, in the production method for a light reflective film ofthe invention, alight reflective layer having a desired helical pitchcan be formed by controlling the type and the concentration of thematerials (mainly the liquid crystal material and the chiral agent) foruse for forming the light reflective layer. The cholesteric liquidcrystal phase having a desired optical rotation may be made by selectingthe chiral agent or the liquid crystal material itself. The thickness ofthe layer may be made to fall within the desired range by controllingthe coating amount.

<Step (c)>

The production method of the invention includes (c) a step of drying theapplied curable liquid crystal composition to be in a state of acholesteric liquid crystal phase.

In an embodiment where the curable liquid crystal composition isprepared as a coating liquid that contains a solvent, the coating filmmay be dried to remove the solvent thereby providing the intendedcholesteric liquid crystal phase state. If desired, the coating film maybe heated so that it may reach the transition temperature into acholesteric liquid crystal phase. For example, the film may be onceheated up to a temperature of an isotropic phase, and thereafter it maybe cooled to the cholesteric liquid crystal phase transitiontemperature, whereby the coating film may be stably made to be in astate of a cholesteric liquid crystal phase. The liquid crystal phasetransition temperature of the curable liquid crystal composition ispreferably within a range of from 10 to 250° C. form the viewpoint ofthe production aptitude, more preferably within a range of from 10 to150° C. When the temperature is lower than 10° C., an additional coolingstep may be necessary for lowering the composition to be in atemperature range in which the composition exhibits a liquid crystalphase. When the temperature is not higher than 200° C., then the coatingfilm does not require a higher temperature than the temperature rangewhere the composition exhibits a liquid crystal phase, in order that thecomposition could be once in an isotropic liquid state at such a hightemperature, and therefore waste of heat energy, and deformation anddegradation of light-transmissive support could be prevented.

<Step (d)>

The production method of the invention includes (d) a step of promotingthe curing reaction of the curable liquid crystal composition to fix thecholesteric liquid crystal phase thereby forming a light reflectivelayer.

The method of promoting the curing reaction of the coating film that isin the above-mentioned state of a cholesteric liquid crystal phase isnot specifically defined, for which any known method is employable.Above all, preferred is a method of irradiating the composition with UVray.

For the UV irradiation, employable is a light source such as a UV lamp,etc. In this step, the curing reaction of the liquid crystal compositionis promoted by irradiation with UV ray, whereby the cholesteric liquidcrystal phase is fixed to form a light reflective layer.

Not specifically defined, the UV irradiation energy dose is, in general,preferably from 100 mJ/cm² to 800 mJ/cm2 or so. The time for which thecoating film is irradiated with UV ray is not also specifically definedbut may be defined from the viewpoint of both the sufficient strength ofthe cured film and the producibility thereof.

The wavelength of the UV ray is not also specifically defined. Dependingon the use application of the light reflective film and on the strengthafter curing that is needed for the light reflective film, UV ray havinga specific wavelength may be cut off by the use of a UV cutoff filter ora resin film having UV absorbability.

For promoting the curing reaction, the UV irradiation may be attainedunder heat. Preferably, the temperature during the UV irradiation is socontrolled as to fall within a temperature range within which thecholesteric liquid crystal phase is not disordered but can be kept wellas such. The oxygen concentration in the atmosphere may have someinfluence on the degree of polymerization, and therefore, in case wherethe desired degree of polymerization could not be attained in air andthe film strength is insufficient, it is desirable that the oxygenconcentration in the atmosphere is lowered according to a method ofnitrogen purging or the like. The preferred oxygen concentration is atmost 10%, more preferably at most 7%, most preferably at most 3%. Thereactivity of the curing reaction (for example, polymerization reaction)to be promoted by the UV irradiation is preferably at least 70%, fromthe viewpoint of securing the mechanical strength of the layer andpreventing any unreacted substance from flowing away from the layer,more preferably at least 80%, even more preferably at least 90%. Forincreasing the reactivity, effectively employed is a method ofincreasing the UV irradiation dose or a method of attaining thepolymerization in a nitrogen atmosphere or under heat. Also employableis a method of heating the film after polymerization, at a temperaturehigher than the polymerization temperature to further promote thethermal polymerization, or a method of again irradiating the film withUV ray (provided that the re-irradiation is attained under the conditionthat satisfies the condition of the invention). The reactivity may bedetermined by measuring the absorption intensity of the IR vibrationalspectrum of the reactive group (for example, polymerizable group) beforeand after the reaction and comparing the found data.

In the above step (d), the cholesteric liquid crystal phase is fixed toform the light reflective layer. In this, in the “fixed” state of theliquid crystal phase, the alignment of the liquid crystal compound inthe state of the cholesteric liquid crystal phase is in the most typicaland most preferred state. Not limited thereto, the state further meansthat, concretely at from 0° C. to 50° C., or under a more severecondition falling within a temperature range of from −30° C. to 70° C.,the layer loses flowability and does not undergo any alignment change byany external field or external force, or that is, the layer continues tostably keep the fixed alignment state thereof. In the invention, thealignment state of the cholesteric liquid crystal phase is fixed by thecuring reaction to be promoted by UV irradiation.

In the invention, it is enough that the optical properties of thecholesteric liquid crystal phase are kept in the layer, and it isunnecessary that the liquid crystal composition in the layer couldfinally exhibit liquid crystallinity. For example, the liquid crystalcomposition may be polymerized by the curing reaction and may lose theliquid crystallinity thereof.

<Step (e)>

The production method of the invention includes (e) a step of repeatingat least once the process of the step (b) to the step (d) on thelaminate having the light reflective layer formed thereon.

In the step (e) in the production method of the invention, a lightreflective film 1 having at least two light reflective layers 14 a and14 b each with a cholesteric liquid crystal phase fixed therein can beproduced, as in FIG. 1 to be described below. Repeating the step gives alight reflective film having at least four light reflective layers as inFIG. 2.

Needless-to-say, not limited to the embodiments of the light reflectivefilm shown in FIGS. 1 to 3 and to the embodiments of the productionmethod described in detail hereinabove, the production method of theinvention is usable for production of any and every type of lightreflective film having at least two light reflective layer each with acholesteric liquid crystal phase fixed therein.

(Relationship Between Plural Light Reflective Layers)

In the production method of the invention, preferably, in the process ofthe above-mentioned steps (b) to (e), at least one layer of reflecting aright circularly-polarized light and at least one layer of reflecting aleft circularly-polarized light are formed. For example, this isdescribed with reference to FIG. 1 and FIG. 2. For forming the lightreflective layer 14 b on the surface of the light reflective layer 14 a,a curable liquid crystal composition is applied thereon. Like that forthe light reflective layer 14 a, the curable liquid crystal compositionalso contains a dextrorotatory or levorotatory chiral agent, and/or anasymmetric carbon atom-having liquid crystal material in order toexhibit a cholesteric liquid crystal phase. In particular, thecomposition preferably contains a chiral agent of which the direction ofoptical rotation differs from that of the chiral agent for use informing the light reflective layer 14 a. For example, in an embodimentwhere the liquid crystal composition for forming the light reflectivelayer 14 a contains a dextrorotatory chiral agent, the composition forthe layer 14 b preferably contains a levorotatory chiral agent; and inan embodiment where the liquid crystal composition for forming the lightreflective layer 14 a contains a levorotatory chiral agent, thecomposition for the layer 14 b preferably contains a dextrorotatorychiral agent.

Preferably, the layer of reflecting a right circularly-polarized lightand the layer of reflecting a left circularly-polarized light areadjacent to each other. In this embodiment, the two light reflectivelayers both have a helical pitch on the same level and each have opticalrotation in the direction opposite to each other. This embodiment ispreferred as being capable of reflecting any of left and rightcircularly-polarized light having a wavelength on the same level. Forexample, there may be mentioned an example of this embodiment where onelight reflective layer is formed of a curable liquid crystal compositioncontaining a dextrorotatory chiral agent and the other light reflectivelayer is formed of a curable liquid crystal composition containing alevorotatory chiral agent, and the helical pitch of these lightreflective layer is on the same level. In case where the film has atleast two pairs of the neighboring two light reflective layers of thosetypes and where the pairs differ in point of the helical pitch of theconstitutive layer, the wavelength band of the light to be reflected maybe broadened and the film could exhibit broadband light reflectivity.

(Winding)

Preferably, the production method of the invention includes a step ofwinding up the film into a roll. The winding method is not specificallydefined.

In one embodiment, for example, the film may be wound up into a rollaround a winding core having a diameter of from 80 to 300 mm.

The timing for the winding is not also specifically defined. Forexample, the film may be wound up in every cycle of the steps (b) to(d), or may be wound up after repetition of plural cycles of the steps(b) to (d) to form a laminate of two or more light reflective layers. Inany of those embodiments, the production method of the invention canexhibit the intended effect.

The winding may be attained before commercial release of the film asfinal products, or that is, the light reflective film of the inventionto be described below may be in the form of a roll.

[Light Reflective Film]

The light reflective film of the invention is produced according to theproduction method of the invention. The light reflective film of theinvention is described below.

Examples of the light reflective film produced according to theproduction method are shown in FIG. 1 and FIG. 2.

The light reflective film 1 shown in FIG. 1 has light reflective layers14 a and 14 b each having a cholesteric liquid crystal phase fixedtherein and repeatedly laminated as at least two layers on one surfaceof a resin film 12, and has a antistatic layer 11 formed on the othersurface of the resin film 12 having no light reflective layer thereon.The light reflective film 1 shown in FIG. 2 additionally has lightreflective layers 16 a and 16 b each having a cholesteric liquid crystalphase fixed therein. The light reflective film of the invention is notlimited to these embodiments, and an embodiment having 6 or more lightreflective layers formed therein is also preferred. On the other hand,odd numbers of such light reflective layers may be formed. The lightreflective film 1 shown in FIG. 3 additionally has a hard coat layer 10on the antistatic layer 11 of the light reflective film shown in FIG. 2.In the invention, the hard coat layer 10 is preferably formed on theantistatic layer 11 by coating.

In the light reflective film 1 shown in FIGS. 1 to 3, each lightreflective layer has a cholesteric liquid crystal phase fixed therein,and therefore the film exhibits light-selective reflectivity ofreflecting a light having a specific wavelength, based on the helicalpitch of the cholesteric liquid crystal phase therein. For example, incase where the neighboring light reflective layers (14 a and 14 b, 16 aand 16 b) have a helical pitch on the same level and have opticalrotation in the direction opposite to each other, the embodiment ispreferred as capable of reflecting both left and rightcircularly-polarized light having a wavelength on the same level. Forexample, there may be mentioned one example of the light reflective film1 of FIG. 1 in which the light reflective layer 14 a of the lightreflective layers 14 a and 14 b is formed of a liquid crystalcomposition containing a dextrorotatory chiral agent and the lightreflective layer 14 b is formed of a liquid crystal compositioncontaining a levorotatory chiral agent and in which the light reflectivelayers 14 a and 14 b both have a helical pitch on the same level of d₁₄nm.

There may be also mentioned one example of the light reflective film 1of FIG. 2, in which the relationship between the light reflective layers14 a and 14 b is the same as that in the light reflective film 1 of FIG.1 mentioned above, in which the light reflective layer 16 a is formed ofa liquid crystal composition containing a dextrorotatory chiral agentand the light reflective layer 16 b is formed of a liquid crystalcomposition containing a levorotatory chiral agent, and in which thelight reflective layers 16 a and 16 b both have a helical pitch on thesame level of d₁₆ nm, satisfying d₁₄≠d₁₆. The light reflective film 1 ofFIG. 2 satisfying the condition exhibits the same effect as that of theabove-mentioned light reflective film 1 of FIG. 1, and furtheradvantages thereof are that the wavelength band of the light to bereflected is broadened owing to the light reflective layers 16 a and 16b existing therein and the film exhibits light reflectivity of widerbandwidth.

The light reflective film produced according to the production method ofthe invention exhibits selective reflectivity characteristics based onthe cholesteric liquid crystal phase in each constitutive layer. Thelight reflective film of the invention may have layers with any ofright-torsion or left-torsion cholesteric liquid crystal phase fixedtherein. Preferred is an embodiment where the film has layers withright-torsion or left-torsion cholesteric liquid crystal phase fixedtherein at the same helical pitch, since the film of the embodiment hashigh selective reflectance to a light having a specific wavelength. Alsopreferred is an embodiment where the film has a plural pairs of layerswith right-torsion or left-torsion cholesteric liquid crystal phasefixed therein at the same helical pitch, since the selective reflectanceof film of the embodiment can be further increased and the selectivereflectivity wavelength band may be further broadened to be wider.

The direction of the optical rotation of the cholesteric liquid crystalphase may be controlled depending on the type of the rod-shaped liquidcrystal or on the type of the chiral agent to be added; and the helicalpitch may be controlled depending on the concentration of theconstitutive materials.

(Properties)

The total thickness of the light reflective laminate film is notspecifically defined. In an embodiment having 4 or more layers each witha cholesteric liquid crystal phase fixed therein and having lightreflectivity in a broad IR reflection range, or that is, having heatshieldability, the thickness of each layer may be from 3 to 6 μm or so,and the total thickness d₃ of the light reflective lamination film couldbe generally from 15 to 40 μm or so.

The selective reflection wavelength of each layer of the lightreflective film of the invention is not specifically defined. Bycontrolling the helical pitch depending on the intended purpose, thefilm may be made to have reflectivity to a light having a desiredwavelength. In one embodiment of the film of the invention, at least onelayer is a so-called IR-reflective film capable of reflecting a part ofthe light having a wavelength of at least 800 nm and falling within anIR wavelength region, and the film of this embodiment exhibits lightshieldability owing to that layer therein. One example of the lightreflective film of the invention can reflect at least 80%, preferably atleast 90% of sunlight having a wavelength of from 900 nm to 1160 nm.Based on this property, when a window film is formed of the film of theinvention, then it has a shielding coefficient of 0.7 or less, asdefined in JIS A-5759 (films for building windowpanes), and cantherefore attain high heat shieldability.

The light reflective film of the invention has a low haze, thoughprocessed for repeated winding up into a roll and unrolling, andconcretely has a haze of less than 0.8%. The light reflective film to bestuck to windowpanes or the like is required to be transparent, and thehaze thereof is preferably lower. The haze is preferably at most 0.6%,more preferably at most 0.55%. The haze may be measured according to JISK7136:2000 (measurement of haze of plastic transparent materials).

(Configuration)

Regarding the configuration thereof, the light reflective film of theinvention may be in the form of a wide-spread sheet or a wound-up roll,but is preferably in the form of a wound-up roll. More preferably, thelight reflective film of the invention can keep good optical propertieseven when stored and transported in the form of a wound-up roll afterits production, in addition to having good optical properties afterrepeated operation of winding up into a roll and unrolling in theproduction process thereof.

The light reflective film of the invention may be a self-supportingmember capable of being used as a window part by itself, or may be amember that is not self-supporting by itself but is stuck to aself-supporting substrate such as a glass plate or the like.

(Use)

The use of the light reflective film of the invention is notspecifically defined.

In using it, the light reflective film of the invention may be stuck tothe surface of a glass plate, a plastic substrate or the like. In thisembodiment, the surface of the heat-shielding member to be stuck to aglass plate or the like is preferably adhesive. In this embodiment,preferably, the light reflective film of the invention has an adhesivelayer, an easy adhesion layer or the like capable of being stuck to thesurface of the substrate such as a glass plate or the like.Needless-to-say, the light reflective film of the invention that is notadhesive may be stuck to the surface of the glass plate using anadhesive therebetween.

Preferably, the light reflective film of the invention has heatshieldability against sunlight, and more preferably, the film can wellreflect the IR ray of 700 nm or more of sunlight.

The light reflective film of the invention can be used as aheat-shielding windowpane of itself for vehicles or buildings, or as asheet or a film to be stuck to the windowpanes of vehicles or buildingsfor the purpose of imparting heat shieldability thereto. In addition,the film may also be used for freezer showcases, materials for plasticgreenhouses for agricultural use, reflective sheets for agriculturaluse, films for solar cells, etc. Among them, the light reflective filmof the invention is favorably used as a light reflective film to bestuck to windowpanes, from the viewpoint of the characteristics of highvisible light transmittance and low haze thereof.

In using the light reflective film of the invention in laminated glass,the film may be inserted directly as it is thereinto, or only thecholesteric layer may be peeled off and transferred thereonto.

In case where the light reflective film of the invention is used inlaminated glass, the film may have an easy adhesion layer containing apolyvinyl butyral as at least one outermost layer. In general, laminatedglass may be produced by heat-adhering two glass sheets via aninterlayer film provided between them. In case where a laminate that hasone or more light reflective layers each having a cholesteric liquidcrystal phase fixed therein is inserted into the inside of laminatedglass, the surface of the light reflective layer is heat-adhered to theinterlayer film, but the adhesion force between them is insufficient,and therefore, when the laminated glass of the type is exposed tonatural light for a long period of time and when its temperature rises,bubbles may be generated between the light reflective film and theinterlayer film so that the transparency of the laminated glass may bethereby lowered. When an easy adhesion layer is formed as the outermostlayer of the light reflective film of the invention, the surface of theeasy adhesion layer may be heat-adhered to the interlayer film ininserting the film into the laminated glass, and therefore the adhesionforce can be increased and eventually the lightfastness of the laminatedglass can be thereby enhanced.

EXAMPLES

The characteristics of the invention are described more concretelyhereinunder with reference to Examples and Comparative Examples.(Comparative Examples are not always examples of known arts.) In thefollowing Examples, the material used, its amount and ratio, the detailsof the treatment and the treatment process may be suitably modified orchanged not overstepping the spirit and the scope of the invention.Accordingly, the scope of the invention should not be limitativelyinterpreted by the Examples mentioned below.

Examples 1 to 3, Comparative Examples 1 to 7 1. Production of LightReflective Film (1-1) Formation of Antistatic Layer:

A polyethylene terephthalate support (by FUJIFILM, hereinafter this isreferred to as PET support) having a thickness of 75 μm is prepared, andone surface thereof was processed for glow discharge treatment.

Subsequently, in Examples 1 to 3, a coating liquid having the followingcomposition was applied onto the glow-discharged surface of the supportaccording to a wire bar coating method so that the dry coating amountcould be 1.3 g/m², then dried at 130° C. for 2 minutes, and the driedfilm was UV-cured to form an antistatic layer.

(Composition for Antistatic Layer) Dispersion of electroconductive fine50 parts by mass particles (dispersion in methyl ethyl ketone ofSnO₂/Sb₂O₅ particles having a concentration of 10%; secondary aggregateshaving a primary particle size of 0.005 μm and having a mean particlesize of 0.05 μm) 1,9-Nonanediol acrylate 20 parts by mass DPHA 2 partsby mass Polymerization initiator Irgacure 819 0.2 parts by mass Methylethyl ketone 100 parts by mass Cyclohexanone 20 parts by mass

For controlling the surface energy of the antistatic layer, afluoropolymer, β-(perfluorooctyl)ethyl acrylate (Light Acrylate FA-108,trade name by Kyoeisha Chemical Industry) was added to the antistaticlayer composition, by which the surface energy of the back side of thelight reflective film of Examples, or that is, the surface energy of theantistatic layer thereof was controlled to be the value as in Table 5given below. In this, the surface energy was measured, using anautomatic contact angle meter, Kyowa Interface Science's DM300.

In Comparative Examples 1 to 6, a layer derived from the coating liquidwas laminated on the surface-treated surface of the PET support in thesame manner as in Examples 1 to 3, except that the dispersion ofelectroconductive fine particles was removed from the above-mentionedantistatic layer composition to prepare the coating liquid. In thefollowing Table 5, “no” in the column of the antistatic layer means thatthe layer of the coating liquid thus prepared by removing the dispersionof electroconductive fine particles from the antistatic layercomposition was formed on the surface-treated surface of the PETsupport.

(1-2) Preparation of Coating Liquid (Curable Liquid CrystalComposition):

Coating liquids each having the composition shown in Tables 1 to 3 belowwere prepared.

TABLE 1 Composition of Coating Liquid (A): right circularly-polarizedlight-reflecting layer Material Name of Material (category)(Manufacturer) Amount Rod-shaped liquid RM-257 (Merck) 10.000 parts bymass crystal compound Chiral Agent LC-756 (BASF) adjusted in accordancewith the intended reflection wavelength Polymerization Irg-819  0.419parts by mass Initiator (Ciba Specialty Chemicals) Alignment Compound 1shown  0.016 parts by mass Controlling Agent below Solvent 2-butanone(Wako 15.652 parts by mass Pure Chemicals)

TABLE 2 Composition of Coating Liquid (B): left circularly-polarizedlight-reflecting layer Material Name of Material (category)(Manufacturer) Amount Rod-shaped liquid RM-257 (Merck) 10.000 parts bymass crystal compound Chiral Agent Compound 2 adjusted in shown belowaccordance with the intended reflection wavelength PolymerizationIrg-819  0.419 parts by mass Initiator (Ciba Specialty Chemicals)Alignment Compound 1  0.016 parts by mass Controlling Agent shown belowSolvent 2-butanone (Wako 15.652 parts by mass Pure Chemicals)

TABLE 3 Composition of Hard Coat Layer Coating Liquid Material Name ofMaterial (category) (Manufacturer) Amount Polymerizing DPHA, by NipponKayaku 23.0 parts by mass Monomer Polymerizing PETA, by Nippon Kayaku23.0 parts by mass Monomer Polymerization Irg-819, by Ciba  4.0 parts bymass Initiator Specialty Chemicals Solvent MEK 50.0 parts by massAlignment Controlling Agent: Compound 1 (compound disclosed in JP-A2005-99248)

R¹ R² X O(CH₂)₂O(CH₂)₂(CF₂)₆F O(CH₂)₂O(CH₂)₂(CF₂)₆F NHChiral Agent: Compound 2 (compound disclosed in JP 2002-179668)

(1-3) Application of Curable Liquid crystal Composition to Laminate, andLamination of Light reflective Layers:

In the above-mentioned coating liquids (A) and (B), the concentration ofthe chiral agent was controlled to prepare different coating liquids foruse for forming the respective light reflective layers, which are shownin Table 4 below. The reflectivity and the reflection wave length peakof the individual light reflective layers are also shown therein.

TABLE 4 Reflection Layer Wavelength No. Reflectivity Material Peak 1Right Coating liquid (A)  900 nm circularly-polarized having acontrolled light-reflecting chiral agent layer concentration 2 RightCoating liquid (A) 1030 nm circularly-polarized having a controlledlight-reflecting chiral agent layer concentration 3 Right Coating liquid(A) 1160 nm circularly-polarized having a controlled light-reflectingchiral agent layer concentration 4 Left Coating liquid (B)  900 nmcircularly-polarized having a controlled light-reflecting chiral agentlayer concentration 5 Left Coating liquid (B) 1030 nmcircularly-polarized having a controlled light-reflecting chiral agentlayer concentration 6 Left Coating liquid (B) 1160 nmcircularly-polarized having a controlled light-reflecting chiral agentlayer concentration

Using these coating liquids, the antistatic layer, the PET support andthe light reflective layers of No. 1 to No. 6 were laminated in thatorder, according to the process of the following (a) to (d).

(a) The prepared coating liquid shown in Table 4 was applied onto thesurface of the PET film opposite to the antistatic layer formed on thefilm, at room temperature using a wire bar, in such a manner that thethickness of the dried layer could be from 4 to 5 μm or so;

(b) this was dried at room temperature for 30 seconds, and then heatedin an atmosphere at 85° C. for 4 minutes to form a cholesteric liquidcrystal phase; and

(c) subsequently, at 30° C., using a metal halide lamp by Eye Graphic'sand controlling the output of the lamp, this was irradiated with UV rayin a nitrogen-purged atmosphere at a dose of 250 mJ/cm² to fix thecholesteric liquid crystal phase to thereby form a first layer(underlayer).

(d) The formed first layer was cooled to room temperature, and then thesteps (a) to (c) were repeated to thereby form second to sixth layers inthat order on the first light reflective layer (underlayer).

(1-4) Winding:

After the light reflective layers were thus laminated, the resultinglaminate film was wound up by 100 m around a winding core having adiameter of 167.5 mm into a roll.

As in the above, samples of light reflective films of Examples andComparative Examples were produced.

2. Evaluation of Light reflective Film (2-1) Coatability and Quality ofHard Coat Layer:

As a hard coat material, the coating liquid shown in Table 3 was appliedonto the antistatic layer so as to have a dry film thickness of 6 μm.The coating condition (smoothness) of the surface of thus-formed hardcoat layer was checked; and the cissing, if any, in coating with thehard coat material was also checked. Thus analyzed, the samples wereevaluated based on the following standards, and the results are shown inTable 5 below. In the invention, the samples are desired to be all given“A” for practical use.

(Smoothness)

A: No roughness was seen in visual reflected light inspection.B: Some roughness was seen weakly in visual reflected light inspection.C: Roughness was seen strongly in visual reflected light inspection.

(Cissing)

A: No microdefects caused by lack of hard coat layer were seen inoptical microscopy.B: A few microdefects caused by lack of hard coat layer were seen in thevisual field in optical microscopy.C: Tens or more microdefects caused by lack of hard coat layer were seenin the visual field in optical microscopy.

(2-2) Reflectance:

Regarding heat shieldability, the solar reflectance of a coating film iscomputed generally according to the calculation method described in JISR 316:1998 “Method for Testing Transmittance, Reflectance, Emissivity,and Solar Acquisition of Sheet Glasses”; and accordingly, the heatshieldability was determined according to the test method. For themeasurement, used was a spectrophotometer equipped with an integratingsphere accessory device.

The film to be analyzed was wound up into a roll around a winding corehaving a diameter of 167.5 mm, then stored at room temperature for 1hour, and unrolled, and the thus-unrolled film was analyzed as thesample thereof. For measuring the reflectance thereof, the film notcoated with the hard coat material on the antistatic layer thereof waswound up into a roll, and analyzed.

The following Table 4 shows the reflectivity measured at a wavelength offrom 900 nm to 1160 nm.

(2-3) Haze:

When the alignment of cholesteric liquid crystal layer worsens, then notonly the reflectance lowers but also the haze remarkably increases.Accordingly, as the index of alignment of cholesteric liquid crystallayer, the haze of the entire light reflective film was measured. Thehaze was measured according to JIS K7136:2000 (Method for Measuring Hazeof Plastic Transparent Materials).

The film to be analyzed was wound up into a roll around a winding corehaving a diameter of 167.5 mm, then stored at room temperature for 1hour, and unrolled, and the thus-unrolled film was analyzed as thesample thereof. For measuring the haze thereof, the film not coated withthe hard coat material on the antistatic layer thereof was wound up intoa roll, and analyzed.

The obtained results are shown in Table 5 below. In Table 5, in thecolumn of haze, “A” means that “the film was highly transparent and ison a practicable level for film for windowpanes”; and “B” means that“the film was whitish owing to scattering (mainly owing to internalscattering), and is unsatisfactory for use as film for windowpanes”. Inthe column of haze, the parenthesized value means the haze value of thelaminate film alone of the six light reflective layers (cholestericliquid crystal layers), No. 1 to No. 6; and this was measured byremoving the laminate film of cholesteric liquid crystal layers from theresin film (laminate of PET support and hard coat layer), and analyzingthe thus-isolated laminate film with a haze meter.

TABLE 5 Back Evaluation Light reflective Layer Surface Coating of TotalEnergy of Antistatic Layer Number of Thickness Antistatic Film with HardCoat Reflectance Haze Layers (type) (mm) Layer (mN/m) Layer (%) (%)Example 1 6 layers 0.03 yes 48 Smoothness A 93% 0.53 (Nos. 1 to 6)Cissing A A (0.28) A Example 2 6 layers 0.03 yes 42 Smoothness A 93%0.55 (Nos. 1 to 6) Cissing A A (0.3)  A Example 3 6 layers 0.03 yes 35Smoothness A 93% 0.54 (Nos. 1 to 6) Cissing A A (0.29) A Comparative 6layers 0.03 no 28 Smoothness B 78% 0.76 Example 1 (Nos. 1 to 6) CissingB C (0.51) B Comparative 6 layers 0.03 no 21 Smoothness C 83% 0.65Example 2 (Nos. 1 to 6) Cissing C B (0.4)  B Comparative 6 layers 0.03no 10 Smoothness C 92% 0.56 Example 3 (Nos. 1 to 6) Cissing C A (0.31) AComparative 6 layers 0.03 no 35 Smoothness A 69% 0.98 Example 4 (Nos. 1to 6) Cissing A C (0.73) C Comparative 6 layers 0.03 no 42 Smoothness A53% 1.45 Example 5 (Nos. 1 to 6) Cissing A C (1.2)  C Comparative 6layers 0.03 no 48 Smoothness A 41% 2.15 Example 6 (Nos. 1 to 6) CissingA C (1.9)  C Comparative 6 layers 0.03 yes 28 Smoothness B 90% 0.56Example 7 (Nos. 1 to 6) Cissing B A (0.31) A

From Table 5, it is known that, in the light reflective films of theinvention, a hard coat layer of high smoothness can be formed on theantistatic layer thereof with no cissing, and the films exhibitbroadband light reflectivity and good reflection performance and havelow haze.

On the other hand, in the films of Comparative Examples 1 to 3, not anantistatic layer but a layer not containing electroconductive fineparticles is formed on the back of the PET support and the surfaceenergy of the layer is on a level lowered from 30 mN/m in order; and itis known that the reflectance of the films of Comparative Examples 1 to3 is increased in that order and the haze thereof is lowered also inthat order, but the hard coat layer formability in these ComparativeExamples is not good. In the films of Comparative Examples 4 to 6, notan antistatic layer but a layer not containing electroconductive fineparticles is formed on the back of the PET support and the surfaceenergy of the layer is on a level increased from 30 mN/m in order; andit is known that the reflectance of the films of Comparative Examples 4to 6 is lowered in that order and the haze thereof is increased also inthat order. Further, from Comparative Example 7, it is known that whenthe surface energy of the antistatic layer is low, then the smoothnessof the layer is poor and the layer has a problem of cissing in coating.

From the above, it is known that, in Examples 1 to 3, the surface energywas increased, surprisingly, however, the reduction in reflectance andthe increase in haze as in Comparative Examples 1 to 6 were not seen inthese Examples, but rather in these, the films kept good reflectance andlow haze. From these, it is understood that the invention satisfies boththe requirement of improving the optical properties and the requirementof improving the hard coat layer formability.

While the present invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to oneskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope thereof.

The present disclosure relates to the subject matter contained inJapanese Patent Application No. 2010-164985, filed on Jul. 22, 2010, thecontents of which are expressly incorporated herein by reference intheir entirety. All the publications referred to in the presentspecification are also expressly incorporated herein by reference intheir entirety.

The foregoing description of preferred embodiments of the invention hasbeen presented for purposes of illustration and description, and is notintended to be exhaustive or to limit the invention to the precise formdisclosed. The description was selected to best explain the principlesof the invention and their practical application to enable othersskilled in the art to best utilize the invention in various embodimentsand various modifications as are suited to the particular usecontemplated. It is intended that the scope of the invention not belimited by the specification, but be defined claims set forth below.

1. A method for producing a light reflective film, comprising: (a)forming an antistatic layer having a surface energy of at least 30 mN/mon one surface of a resin film to produce a laminate, (b) applying acurable liquid crystal composition onto the surface of the laminateopposite to the side thereof given the antistatic layer, (c) drying theapplied curable liquid crystal composition to be in a state of acholesteric liquid crystal phase, (d) promoting the curing reaction ofthe curable liquid crystal composition to fix the cholesteric liquidcrystal phase thereby forming a light reflective layer, and (e)repeating at least once the process of from (b) to (d) on the laminatehaving the light reflective layer formed thereon.
 2. The method forproducing a light reflective film according to claim 1, wherein thecurable liquid crystal composition contains a polymerizable rod-shapedliquid crystal compound, an alignment controlling agent capable ofcontrolling the alignment of the polymerizable rod-shaped liquid crystalcompound, and a solvent.
 3. The method for producing a light reflectivefilm according to claim 1, wherein in the process of the step (b) to thestep (e), at least one layer of reflecting a right circularly-polarizedlight and at least one layer of reflecting a left circularly-polarizedlight are formed.
 4. The method for producing a light reflective filmaccording to claim 1, which comprises aligning the surface of thelaminate on the side opposite to the side thereof having the antistaticlayer formed thereon, between the step (a) and the step (b).
 5. Themethod for producing a light reflective film according to claim 1, whichcomprises forming an alignment film on the laminate on the side oppositeto the side thereof having the antistatic layer formed thereon, andaligning the surface of the alignment film, between the step (a) and thestep (b).
 6. The method for producing a light reflective film accordingto claim 4, which comprises aligning the surface of the laminate byrubbing treatment.
 7. The method for producing a light reflective filmaccording to claim 1, which comprises forming the antistatic layer bycoating an antistatic layer composition.
 8. The method for producing alight reflective film according to claim 1, which comprises forming theantistatic layer by using an antistatic layer composition containingelectroconductive fine particles.
 9. The method for producing a lightreflective film according to claim 8, wherein the antistatic layercomposition contains an electroconductive polymer.
 10. The method forproducing a light reflective film according to claim 8, wherein theelectroconductive fine particles contain SnO₂ and Sb₂O₅.
 11. The methodfor producing a light reflective film according to claim 1, whichcomprises forming the antistatic layer by using an antistatic layercomposition containing a difunctional or more polyfunctionalpolymerizable monomer.
 12. The method for producing a light reflectivefilm according to claim 11, wherein the polymerizable monomer is adifunctional or more polyfunctional (meth)acrylate.
 13. The method forproducing a light reflective film according to claim 11, wherein thepolymerizable monomer is at least one of dipentaerythritol hexaacrylateand pentaerythritol tetraacrylate.
 14. The method for producing a lightreflective film according to claim 1, which comprises forming theantistatic layer by using an antistatic layer composition containing afluorine compound.
 15. The method for producing a light reflective filmaccording to claim 1, wherein the resin film is a polyethyleneterephthalate film.
 16. The method for producing a light reflective filmaccording to claim 1, which comprises forming a hard coat layer on thesurface of the resin film opposite to the side of the antistatic layerthereof.
 17. The method for producing a light reflective film accordingto claim 1, which is for producing a light reflective film to be stuckto windowpanes.
 18. The method for producing a light reflective filmaccording to claim 1, which comprises winding up the film into a roll.19. A light reflective film produced by: (a) forming an antistatic layerhaving a surface energy of at least 30 mN/m on one surface of a resinfilm to produce a laminate, (b) applying a curable liquid crystalcomposition onto the surface of the laminate opposite to the sidethereof given the antistatic layer, (c) drying the applied curableliquid crystal composition to be in a state of a cholesteric liquidcrystal phase, (d) promoting the curing reaction of the curable liquidcrystal composition to fix the cholesteric liquid crystal phase therebyforming a light reflective layer, and (e) repeating at least once theprocess of from (b) to (d) on the laminate having the light reflectivelayer formed thereon.
 20. The light reflective film according to claim19 wound up into a roll.